"The ACCC has updated their econometrics on FuelWatch and it reinforces the positive effects of that policy found in WA. The new updates do two things:

First, they respond to claims that price falls in WA were the result of the entry of Coles rather than FuelWatch. The ACCC uses a test for endogenous structural breaks to look for significant events. They find that both Coles’ entry and FuelWatch were such events but that FuelWatch’s effect was almost three times as large.

Second, the ACCC looks at the highs and lows of the petrol price cycle. They find that the introduction of FuelWatch in WA, not only reduced prices by 3.5 cents per litre on high priced days it reduces prices by 0.7 cents per litre on low priced days. So that means that even bargain hunters were better off."

There is other interesting information out today as well...
Made public by the Coalition Consumer Affairs spokesman Luke Hartsuyker, it is ACCC data on what volumes of petrol were bought for what prices in Sydney vs Perth during the month of August 2007.

The ACCC couldn't make use of it for its economic analysis because it doesn't go back far enough. But it suggests that the ACCC's ideas about "average" margins in perth vs "average" in eastern states before and after FuelWatch overstate the difference FuelWatch made.

But its conclusions about minimum margins would stand.

Here's the info:

In Sydney 34.5 per cent of petrol is sold for prices in the lowest decile of prices.

In Perth a smaller 18.1 per cent is sold for prices in the lowest decile.

In Sydney 18.1 per cent of petrol is sold for prices in the next lowest decile.

In Perth a smaller 8.5 per cent is sold for prices in the next lowest lowest decile.

In Sydney 15.9 per cent of petrol is sold for prices in the third lowest decile.

In Perth a smaller 9.8 per cent of petrol is sold for prices in the third lowest lowest decile.

Taking the lowest three declies together, in Sydney 65.3 per cent of petrol is sold for those prices; in Perth it is 36.4 per cent.

For the highest-priced decile, in Sydney only 3.1 per cent of petrol was sold; in Perth 11.7 per cent of petrol was sold.